Component	Description
Geological Layer	Thermal erosion simulation
Ecological Layer	9 biome types with spreading rules
Feedback Loop	Forests stabilize terrain (80% resistance)
Renderer	2.5D isometric with atmospheric fog

Cellular Automata Rules

Erosion (Diffusion)

Each cell moves toward neighbor average

float neighborAvg = avgOf8Neighbors();
newH = h + (neighborAvg - h) * rate;

Biomes modify erosion rate

if (biome == FOREST) 
    rate *= forestMult; // UI: 0.2
if (biome == DESERT) 
    rate *= desertMult; // UI: 1.5

Height thresholds + neighbor counting

if (h < 0.30) biome = WATER;
if (h > 0.85) biome = SNOW;
if (forestNeighbors >= threshold)
    if (rand() < forestChance)
        biome = FOREST;

Biome	Behavior
Water	Height < 0.3 (forced)
Sand	Coastal zones
Grass	Default land, converts to forest
Forest	Spreads, resists erosion
Desert	Spreads in dry areas
Rock	High elevation (>0.8)
Snow	Peaks (>0.85)
Tundra	Alpine transition
Wetland	Low areas near water